In order to suppress vibration and rocking which occur during traveling of a vehicle such as a railway vehicle, a linear actuator is used. Suppressing vibration and rocking in a lateral direction with respect to a traveling direction of a vehicle plays an important role to give passengers a comfortable ride and keep safe traveling conditions. In recent years, the study for suppressing rocking and vibration due to the influence of aerodynamic characteristics at the time of high-speed traveling by active control to keep the vehicle attitude stable has been especially advanced. Further, in general, a linear actuator that is used for prevention of rocking of a railway vehicle is used under a severe temperature condition in which the temperature variation of the use environment where it is installed is large (for example, −20C. to 60C.) even though the linear actuator is used under the severe conditions in which maintenance such as frequent replacement is difficult to carry out, and therefore, it is required to keep the function of the linear actuator stable.
Japanese Patent Application Laid-Open No. 2005-75278 (hereinafter Patent Document 11 discloses a pneumatic servo cylinder for a vehicle which generates a force against the oscillation in the lateral direction of a vehicle body. According to the configuration of Patent Document 1, Patent Document 1 indicates that the vehicle is loaded on a bogie truck via an air spring, an pneumatic servo cylinder for a vehicle is installed in a horizontal direction between a centering pin that is installed at a lower part of the vehicle and the bogie truck, an air pressure generating section is installed at an external part of the pneumatic servo cylinder for a vehicle, and compressed air is supplied as the drive source of the servo cylinder.
The controller for a railway vehicle that suppresses the vibration of a vehicle body which Japanese Patent Application Laid-Open No. 2009-101961 (hereinafter Patent Document 2) discloses is such that an electric actuator is installed between the vehicle body and a bogie truck, and the drive force by the electric actuator is controlled, whereby the function as the actuator and the damper is given thereto. Patent Document 2 indicates that as the electric actuator, the controller has the mechanism which converts rotation of the motor into a linear motion by using a ball screw, a roller screw or the like, and is caused to have the same role as the damping force of a damper with the resistance of friction or the like of the converting section.